Electrical connector



Al1g- 7, 1952 G. R. HI-:IDLER 3,048,812

ELECTRICAL CONNECTOR Filed July 16, 1959 INNIIIIIIIIIIIIFIIIIIMMIIIIIIIIIHIIIIIIIIIIIIWIIIIIHIIIMW j r MMIII`||I||||IIIIIIIIIIIIIIIIIIIIIIIIIIIIIWAIIIHIIIIIIIIIIIIIIIIIII [I |l||||||||||lIIIIIIIIIIIIIIIImIIIIIIIIWIIIIIIIIIIFIIIIHIIIIIIIIIIIIIIM il! I|| I IIIHIIIIIIIIIIIIIIIIIIV IIIIIIIiHUI||||||IIIHIIIIIIIIIIIIIIIIIIIIIIIIIIIIMMIMIIIIHIIIIIIIIIIIIII INVENTOR.

:@: .GLEN R. HI-:IDLER AGENT United States Patent G 3,048,812 ELECTRICAL CONNECTOR Glen R. Heidler, Paoli, Pa., assignor to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Filed July 16, 1959, Ser. No. 827,602 2 Claims. (Cl. 339-252) The invention hereinafter described and claimed has to do with electrical connectors, and more particularly to connectors of the type primarily useful in interconnecting electrical components o1' circuitry.

A problem with the use of electrical and electronic assemblies and sub-assemblies is the lack of reliability of the interconnection between components forming the subassemblies and even between the sub-assemblies themselves. Such lack of reliability has been suspect in the -failure of some of the costly missiles tired from Cape Canaveral, Florida, in recent years. Because of these failures the responsible engineers are increasingly conscious of the need for more reliable means for making such interconnections thus to put an end to failures from this cause.

Many of such interconnections are of the permanently soldered or welded type, and these are fairly reliable. However, we are concerned here with the pressure contact type where electrically conductive interconnections are by pressure of one conductor against another. Plug-in connectors are a common example of this type of interconnector. However, such devices usually rely upon only one, and rarely more than two points of contact for such interconnection.

Therefore it is an important object of the present invention to provide an electrical connector overcoming the above-mentioned ditliculty by a construction effecting interconnection of electrically conductive elements with a high degree of reliability.

It is also an object of the invention to provide an electrical connector wherein such reliability is obtained by a construction including a multiplicity of contact points automatically eifective to wipe themselves into good electrically conductive contact with the device to which it is being connected.

Another object of the invention is to provide such an electrical connector which is useful both as a plug-in or as a pressure type of connector wherein the connector is compressed between two adjacent elements in the manner of a sandwich.

Still another object of the invention is to provide an electrical connector having multiple contact points of high density, that is, wherein the many contact points are closely adjacent to each other.

A further object of the invention is to provide an electrical connector which is self-centering in all of its applications.

More specifically it is an object of the invention to provide an electrical connector of extremely small size and which is of negligible cost.

In accordance with the above objects and first briefly described, the invention comprises a thin generally flat plate of highly flexible metal, such as beryllium copper, provided with a number of integral and parallel ribbonlike portions bent to form undulating or zig-zag strips having high and low portions similar to the warp of a woven basket. That is, the highs and lows of successively adjacent strips are 180 out of phase, thus to form an electrical connector having a multiplicity of contact points extending from opposite faces of the connector.

In the accompanying drawings:

FIG. l is a perspective view of a connector embodying the preferred form of the invention;

FIG. 2 is a plan view on a slightly smaller scale of the connector of FIG. l;

FIG. 3 is a side elevation view of the connector of FIG. l;

FIG. 4 is a view showing various modifications of the connector;

FIG. 5 shows the preferred form of the invention when used as a plug-in connector; and

FIG. 6 is a view showing the preferred form of the invention used as a pressure type connector.

More specifically and with reference to FIGS. l, 2 and 3, it will be seen that the preferred form of the invention comprises an elongated member 10 formed of any thin suitable metal, such as beryllium copper, which may lbe plated, if desired, with a metal such as gold. The element has been slitted adjacent the right hand end, as indicated at 11, to form four ilexible ribbon-like portions or strips 12, 13, 14 and 1S, aligned in a plane extending transversely across the connector. While in this form of the invention the strips are equal in width and length, it should be understood that for some applications it may be desirable to form them of diierent dimensions, and such is contemplated within the scope of the invention.

Each of these strips, as seen more clearly in FIGS, l and 3, has been bent, or otherwise formed in an undulating pattern including alternate peaks and valleys, 16 and 17 respectively, when viewing one face of the strip, as seen in FIG. 2. Alternate adjacent strips, in this form of the invention, are oppositely formed so that the peaks of every other strip are aligned in a plane extending at right angles to and transversely across the connector 10 with the valleys in the other strips, and vice verse. In other words, the peaks 16 of strips 13y and 15 are transversely aligned -with the valleys=17 of strips 12 and 14 at positions 18 and 20, of FIG. 2. While at position 21, between positions 1-8 and 20, the valleys 17 of strips 13 and 15 are aligned with the peaks 16 of strips 12 and 14. Of course the valleys and peaks are oppositely disposed when looking at the opposite side of the connector.

By forming the strips in the manner above-described, it will be seen that each is self-centering in use by reason of its three-point contact with associated apparatus, as seen in FIGS. 5 and 6. Each peak of the connector is also effective to provide a wiping contact with the associated apparatus, as more fully described later, regardless of whether it is used as a plug-in or as a pressure type connector. Additionally, the connector provides a multiplicity of contact points-twelve in this illustrated preferred embodiment-thus to measurably increase its reliability over other known connectors.

With reference again to FIG. 2, it will be seen that the strips preferably are located at the right hand portion of the element y10 but short of its terminal end 22. In the left hand portion 23 of the connector there is provided an aperture 24 for mechanically securing the connector to associated apparatus by means of la screw or similar connecting device. Alternatively, the end 23 may be soldered or welded to lassoci-ated apparatus.

While the invention is capable of expression in other proportions, the miniature size in which it is capable of being embodied may be illustrated by .the following dimensions, by way of example, Iand with reference to FIGS. 2 and 3, wherein: dimension A=.003; B=.080; C=.l80"; E=.014"; F=.0l6; and G=any desired dimension. It will `be noted that dimension F at station 21 in this preferred form of the invention is slightly larger than dimensions E Ialthough the invention contemplates a construction wherein they yare equal. Making dimension F slightly larger than E has the eiect under some conditions to equalize the forces against peaks 16 at the E dimensions-stations 18 and 20 (FIG. 2). This can be illustrated by pressing peaks 16 at station 21 toward each other. Such pressure will cause peaks 16 at both E dimensions (stations 18 and 20) to separate `and become equal to or even greater-if not restrained-than dimension F. On the other hand if peaks 16 at station 18 o-r 20 are pressed toward each other, the E dimension at that station is decreased while Ithe F dimension increases. Thus the preferred construction illustrated contributes to the self-centering of the connector under some conditions of use.

Overall, and by way of comparison, the whole connector with its plurality of contact points, when constructed in accordance with the above dimensions, is of a size considerably less than that of `a paper match taken from a normal size book of matches.

The contact peaks of the strips in this preferred form, as seen in FIG. 3, are formed by rather sharp bend-s while the connecting portions are substantially straight. However, as illustrated in FIG. 4, showing only a few examples, it will be seen that the strips may ybe formed in a variety of shapes to suit lany particular application.

With reference now to FIGS. 5 and 6, illustrating examples of the many uses of the connector, it will be seen in FIG. 5 that the end 23 of the connector may be suitably secured, as by soldering for example, to one end of a printed circuit conductor 26 on panel 27. The contact end of the connector is inserted into one end of a socket 28 with the peaks 16 of the strips pressing against the receptacle 29. 'Ihe end 30 of receptacle 29 extends from the opposite end 31 of the socket for connection to associated circuitry (not shown). In this application the dimensions E and F across aligned peaks 16 (FIG. 3) are greater than the distance between side walls 32 of the receptacle 29, thus to cause the contact points 16 to bear tightly against walls 32 during and after insertion. During insertion of the connector into the receptacle the peaks 16 will wipe across the walls 32 thus to afford an excellent electrically conductive contact between the connector and the receptacle. The self-centering feature of the connector-by reason of the three point contact of each stripis illustrated quite clearly in this figure and also FIG. 6 now to be described.

When using the invention as a contact or pressure type connector as seen in FIG. 6, it may be used in a number of ways, of which two are shown. Here the connectors are shown interconnecting stacked components or subassemblies, such as printed circuit panels 34, 35 and 36. The numeral 37 identities electrically conductive pads positioned along an edge of the panels 34, 35 and 36 for the purpose of providing edge terminals for printed circuitry (not shown) on the opposite faces of the panels. As seen here, one connector 10 is shown with most of its end 23 severed, and its Contact portion sandwiched between and electrically interconnecting pads '37 on panels 34 and 35. Alternatively the connector 10 may be formed without the end 23. It will be recognized that pressing the panels against the connector will cause the connector to contract whereby the peaks 16 on each side of the connector move away from each other and wipe against the pads 37 thus to provide excellent electrical connection between the contact points and the pads. The connector may be held in this position merely by the pressure of the panels, or suitably secured to one or both pads 37 as by soldering or welding.

Still referring to FIG. 6, it will be seen that connector 10" is bent backwardly upon itself in the manner of a hairpin, whereby the peaks 16" on one side of the strips are brought into contact with its own end 2'3", and on the other side with the pad 37 on the edge of the adjacent printed circuit panel 36. Preferably the panels are pressed together to compress the strips whereby the contact peaks 16 are pressed inwardly land therefore spread away from each other, thus to wipe themselves into good electrically conductive contact with the associated pad 37 on panel 36, thereby greatly increasing its reliability. In this form of the invention, end 24 may be firmly iixed to panel 35 and serve as the edge terminal for circuitry printed on the adjacent face of the panel.

Of course, either of connectors 10 or 10" may be used at other positions on the panels to interconnect circuitry on each.

Thus it is seen that the invention provides a self-centering electrical connector capable of manufacture in miniature size and having a high degree of reliability by reason of its multiplicity of closely spaced contact points effective to wipe themselves into good electrically conductive contact with the apparatus which it is interconnecting.

What is claimed is:

1. An electrical connector comprising, a thin generally flat flexible metallic body member having opposite first and second surfaces and a plurality of integral ribbon-like strips formed therein by substantially parallel slits extending through the thickness of and across said member but terminating short of its edges, said strips being formed in successive oppositely undulating patterns with contact forming peaks extending from said opposite surfaces, alternate strips having at least two peaks extending from said first opposite surface and at least one peak extending from said second opposite surface, the remaining strips having at least two peaks extending from said second opposite surface and at least one peak extending from said first opposite surface, said peaks being transversely aligned in a plane transversely across said body member at right angles thereto, said one peak of each of said strips being intermediate the said two peaks of said strip to provide self-centering of said connector, and said intermediate peaks of adjacent strips extending outwardly in opposite directions normal to said generally flat body member a greater distance than other peaks.

2. An electrical connector comprising a thin flexible generally ilat metallic body member having opposite surfaces and a plurality of integral ribbon-like strips formed by substantially parallel slits extending through the thickness of said member, said strips being formed in successive oppositely undulating patterns with peaks extending from both surfaces of said member to form a plurality of electrical contacts on both surfaces, each of said strips having at least two spaced contact forming peaks extending from one of said surfaces and at least one contact forming peak extending from the opposite surface, said one contact peak being between said two contact peaks, and the corresponding peaks on adjacent strips extending in 'opposite directions from the said surfaces of the metallic member, and wherein said one contact peak of each strip extends a greater distance normally from said generally flat body member than said two contact peaks.

References Cited in the le of this patent UNITED STATES PATENTS 2,183,067 Gardner Dec. 12, 1939 FOREIGN PATENTS 403,864 Great Britain Jan. 4, 1934 500,832 Canada Mar. 23, 1954 1,184,311 France Feb. 2, 1959 

